315 lines
8.1 KiB
C++
315 lines
8.1 KiB
C++
// rw.cpp - originally written and placed in the public domain by Wei Dai
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#include "pch.h"
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#include "rw.h"
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#include "asn.h"
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#include "integer.h"
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#include "nbtheory.h"
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#include "modarith.h"
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#include "asn.h"
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#ifndef CRYPTOPP_IMPORTS
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#if defined(_OPENMP)
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# define CRYPTOPP_RW_USE_OMP 1
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#else
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# define CRYPTOPP_RW_USE_OMP 0
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#endif
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NAMESPACE_BEGIN(CryptoPP)
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void RWFunction::BERDecode(BufferedTransformation &bt)
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{
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BERSequenceDecoder seq(bt);
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m_n.BERDecode(seq);
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seq.MessageEnd();
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}
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void RWFunction::DEREncode(BufferedTransformation &bt) const
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{
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DERSequenceEncoder seq(bt);
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m_n.DEREncode(seq);
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seq.MessageEnd();
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}
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Integer RWFunction::ApplyFunction(const Integer &in) const
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{
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DoQuickSanityCheck();
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Integer out = in.Squared()%m_n;
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const word r = 12;
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// this code was written to handle both r = 6 and r = 12,
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// but now only r = 12 is used in P1363
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const word r2 = r/2;
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const word r3a = (16 + 5 - r) % 16; // n%16 could be 5 or 13
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const word r3b = (16 + 13 - r) % 16;
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const word r4 = (8 + 5 - r/2) % 8; // n%8 == 5
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switch (out % 16)
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{
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case r:
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break;
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case r2:
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case r2+8:
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out <<= 1;
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break;
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case r3a:
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case r3b:
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out.Negate();
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out += m_n;
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break;
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case r4:
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case r4+8:
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out.Negate();
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out += m_n;
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out <<= 1;
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break;
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default:
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out = Integer::Zero();
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}
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return out;
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}
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bool RWFunction::Validate(RandomNumberGenerator &rng, unsigned int level) const
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{
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CRYPTOPP_UNUSED(rng), CRYPTOPP_UNUSED(level);
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bool pass = true;
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pass = pass && m_n > Integer::One() && m_n%8 == 5;
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CRYPTOPP_ASSERT(pass);
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return pass;
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}
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bool RWFunction::GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const
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{
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return GetValueHelper(this, name, valueType, pValue).Assignable()
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CRYPTOPP_GET_FUNCTION_ENTRY(Modulus)
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;
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}
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void RWFunction::AssignFrom(const NameValuePairs &source)
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{
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AssignFromHelper(this, source)
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CRYPTOPP_SET_FUNCTION_ENTRY(Modulus)
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;
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}
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// *****************************************************************************
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// private key operations:
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// generate a random private key
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void InvertibleRWFunction::GenerateRandom(RandomNumberGenerator &rng, const NameValuePairs &alg)
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{
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int modulusSize = 2048;
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alg.GetIntValue("ModulusSize", modulusSize) || alg.GetIntValue("KeySize", modulusSize);
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if (modulusSize < 16)
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throw InvalidArgument("InvertibleRWFunction: specified modulus length is too small");
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AlgorithmParameters primeParam = MakeParametersForTwoPrimesOfEqualSize(modulusSize);
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m_p.GenerateRandom(rng, CombinedNameValuePairs(primeParam, MakeParameters("EquivalentTo", 3)("Mod", 8)));
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m_q.GenerateRandom(rng, CombinedNameValuePairs(primeParam, MakeParameters("EquivalentTo", 7)("Mod", 8)));
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m_n = m_p * m_q;
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m_u = m_q.InverseMod(m_p);
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Precompute();
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}
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void InvertibleRWFunction::Initialize(const Integer &n, const Integer &p, const Integer &q, const Integer &u)
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{
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m_n = n; m_p = p; m_q = q; m_u = u;
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Precompute();
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}
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void InvertibleRWFunction::PrecomputeTweakedRoots() const
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{
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ModularArithmetic modp(m_p), modq(m_q);
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// GCC warning bug, https://stackoverflow.com/q/12842306/608639
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#ifdef _OPENMP
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#pragma omp parallel sections if(CRYPTOPP_RW_USE_OMP)
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{
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#pragma omp section
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m_pre_2_9p = modp.Exponentiate(2, (9 * m_p - 11)/8);
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#pragma omp section
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m_pre_2_3q = modq.Exponentiate(2, (3 * m_q - 5)/8);
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#pragma omp section
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m_pre_q_p = modp.Exponentiate(m_q, m_p - 2);
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}
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#else
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m_pre_2_9p = modp.Exponentiate(2, (9 * m_p - 11)/8);
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m_pre_2_3q = modq.Exponentiate(2, (3 * m_q - 5)/8);
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m_pre_q_p = modp.Exponentiate(m_q, m_p - 2);
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#endif
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m_precompute = true;
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}
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void InvertibleRWFunction::LoadPrecomputation(BufferedTransformation &bt)
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{
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BERSequenceDecoder seq(bt);
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m_pre_2_9p.BERDecode(seq);
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m_pre_2_3q.BERDecode(seq);
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m_pre_q_p.BERDecode(seq);
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seq.MessageEnd();
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m_precompute = true;
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}
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void InvertibleRWFunction::SavePrecomputation(BufferedTransformation &bt) const
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{
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if(!m_precompute)
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Precompute();
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DERSequenceEncoder seq(bt);
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m_pre_2_9p.DEREncode(seq);
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m_pre_2_3q.DEREncode(seq);
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m_pre_q_p.DEREncode(seq);
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seq.MessageEnd();
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}
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void InvertibleRWFunction::BERDecode(BufferedTransformation &bt)
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{
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BERSequenceDecoder seq(bt);
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m_n.BERDecode(seq);
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m_p.BERDecode(seq);
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m_q.BERDecode(seq);
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m_u.BERDecode(seq);
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seq.MessageEnd();
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m_precompute = false;
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}
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void InvertibleRWFunction::DEREncode(BufferedTransformation &bt) const
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{
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DERSequenceEncoder seq(bt);
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m_n.DEREncode(seq);
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m_p.DEREncode(seq);
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m_q.DEREncode(seq);
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m_u.DEREncode(seq);
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seq.MessageEnd();
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}
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// DJB's "RSA signatures and Rabin-Williams signatures..." (http://cr.yp.to/sigs/rwsota-20080131.pdf).
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Integer InvertibleRWFunction::CalculateInverse(RandomNumberGenerator &rng, const Integer &x) const
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{
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DoQuickSanityCheck();
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if(!m_precompute)
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Precompute();
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ModularArithmetic modn(m_n), modp(m_p), modq(m_q);
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Integer r, rInv;
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do
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{
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// Do this in a loop for people using small numbers for testing
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r.Randomize(rng, Integer::One(), m_n - Integer::One());
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// Fix for CVE-2015-2141. Thanks to Evgeny Sidorov for reporting.
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// Squaring to satisfy Jacobi requirements suggested by Jean-Pierre Munch.
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r = modn.Square(r);
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rInv = modn.MultiplicativeInverse(r);
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} while (rInv.IsZero());
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Integer re = modn.Square(r);
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re = modn.Multiply(re, x); // blind
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const Integer &h = re, &p = m_p, &q = m_q;
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Integer e, f;
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const Integer U = modq.Exponentiate(h, (q+1)/8);
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if(((modq.Exponentiate(U, 4) - h) % q).IsZero())
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e = Integer::One();
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else
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e = -1;
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const Integer eh = e*h, V = modp.Exponentiate(eh, (p-3)/8);
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if(((modp.Multiply(modp.Exponentiate(V, 4), modp.Exponentiate(eh, 2)) - eh) % p).IsZero())
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f = Integer::One();
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else
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f = 2;
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#ifdef _OPENMP
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Integer W, X;
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#pragma omp parallel sections if(CRYPTOPP_RW_USE_OMP)
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{
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#pragma omp section
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{
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W = (f.IsUnit() ? U : modq.Multiply(m_pre_2_3q, U));
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}
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#pragma omp section
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{
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const Integer t = modp.Multiply(modp.Exponentiate(V, 3), eh);
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X = (f.IsUnit() ? t : modp.Multiply(m_pre_2_9p, t));
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}
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}
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#else
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const Integer W = (f.IsUnit() ? U : modq.Multiply(m_pre_2_3q, U));
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const Integer t = modp.Multiply(modp.Exponentiate(V, 3), eh);
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const Integer X = (f.IsUnit() ? t : modp.Multiply(m_pre_2_9p, t));
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#endif
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const Integer Y = W + q * modp.Multiply(m_pre_q_p, (X - W));
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// Signature
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Integer s = modn.Multiply(modn.Square(Y), rInv);
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CRYPTOPP_ASSERT((e * f * s.Squared()) % m_n == x);
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// IEEE P1363, Section 8.2.8 IFSP-RW, p.44
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s = STDMIN(s, m_n - s);
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if (ApplyFunction(s) != x) // check
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throw Exception(Exception::OTHER_ERROR, "InvertibleRWFunction: computational error during private key operation");
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return s;
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}
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bool InvertibleRWFunction::Validate(RandomNumberGenerator &rng, unsigned int level) const
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{
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bool pass = RWFunction::Validate(rng, level);
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CRYPTOPP_ASSERT(pass);
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pass = pass && m_p > Integer::One() && m_p%8 == 3 && m_p < m_n;
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CRYPTOPP_ASSERT(pass);
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pass = pass && m_q > Integer::One() && m_q%8 == 7 && m_q < m_n;
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CRYPTOPP_ASSERT(pass);
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pass = pass && m_u.IsPositive() && m_u < m_p;
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CRYPTOPP_ASSERT(pass);
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if (level >= 1)
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{
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pass = pass && m_p * m_q == m_n;
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CRYPTOPP_ASSERT(pass);
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pass = pass && m_u * m_q % m_p == 1;
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CRYPTOPP_ASSERT(pass);
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}
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if (level >= 2)
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{
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pass = pass && VerifyPrime(rng, m_p, level-2) && VerifyPrime(rng, m_q, level-2);
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CRYPTOPP_ASSERT(pass);
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}
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return pass;
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}
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bool InvertibleRWFunction::GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const
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{
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return GetValueHelper<RWFunction>(this, name, valueType, pValue).Assignable()
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CRYPTOPP_GET_FUNCTION_ENTRY(Prime1)
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CRYPTOPP_GET_FUNCTION_ENTRY(Prime2)
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CRYPTOPP_GET_FUNCTION_ENTRY(MultiplicativeInverseOfPrime2ModPrime1)
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;
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}
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void InvertibleRWFunction::AssignFrom(const NameValuePairs &source)
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{
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AssignFromHelper<RWFunction>(this, source)
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CRYPTOPP_SET_FUNCTION_ENTRY(Prime1)
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CRYPTOPP_SET_FUNCTION_ENTRY(Prime2)
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CRYPTOPP_SET_FUNCTION_ENTRY(MultiplicativeInverseOfPrime2ModPrime1)
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;
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m_precompute = false;
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}
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NAMESPACE_END
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#endif
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